A TV news program reports on missiles launched by North Korea at Seoul Railway Station in Seoul on July 13, 2014. / Ahn Young-joon, AP

by USA TODAY

by USA TODAY

SEOUL, South Korea (AP) - North Korea launched two ballistic missiles into the sea on Sunday, South Korea said, the latest in a series of test-firings seen as expressions of anger over the North's failure to win talks on receiving outside aid, and over U.S.-South Korean military drills.

The missiles, believed to be of Scud variations, were fired from the North Korean city of Kaesong near the border with the South and had a range of about 500 kilometers (311 miles), said a South Korean military official who spoke on condition of anonymity because of department rules.

North Korea experts said it was highly unusual for Pyongyang to fire missiles from a city just 20 kilometers (12 miles) from the heavily fortified border separating the two Koreas. The North usually test-fires missiles launched from its eastern port city of Wonsan, about 130 kilometers (80 miles) from the border.

"It is remarkable that missiles were fired from Kaesong, a symbol of North-South cooperation," said professor Yang Moo-jin of Seoul's University of North Korean Studies. The jointly-run Kaesong Industrial Complex brings together South Korean-owned companies with North Korean labor. "Such action can mount tensions as it suggests that these missiles ... can target the entire Korean Peninsula. "

North Korea regularly conducts test-firings, but this year has seen an unusually large number of launches. South Korean officials have confirmed about 90 test-firings of missiles, artillery and rockets by the North since Feb. 21. More than 10 of them have been ballistic launches.

North Korea recently has pushed South Korea to accept a set of proposals that it said would reduce bilateral tensions, including the cancellation of regular military drills between Seoul and Washington that Pyongyang insists are preparation for a northward invasion.

Pyongyang's National Defense Commission released a statement Saturday strongly criticizing the U.S.-South Korean joint naval drills that are reportedly to take place in Korean waters beginning Wednesday. The NDC also said the landing of the United States' George Washington Carrier Strike Group in South Korea's port city of Busan was a part of America's "reckless nuclear blackmail and threat."

"Whenever there was a sign of improving the North-South relations and detente on the peninsula, the U.S. resorted to sinister interference and obstructions," said the statement, which was released by the North's official Korean Central News Agency.

Many in South Korea have doubts over how sincere the impoverished North is about its push to reduce tensions, and analysts see the pressure for better ties as meant in part to eventually win much-needed outside aid and investment. South Korea has rejected the North's proposals, saying it must first demonstrate that it is serious about nuclear disarmament if it truly wants peace.

North Korea likely possesses a small arsenal of crude nuclear bombs and is working to build an arsenal of nuclear-tipped missiles that could reach the U.S. mainland.

The Korean Peninsula officially remains in a state of war because the 1950-53 Korean War ended with an armistice, not a peace treaty.

Copyright 2015 The Associated Press. All
rights reserved. This material may not be published, broadcast, rewritten or redistributed.